SCJP......Garbage collection

[srinibash udayasingh]

Given:
1. class Eco {
2. public static void main(String[] args) {
3. Eco e1 = new Eco();
4. Eco e2 = new Eco();
5. Eco e3 = new Eco();
6. e3.e = e2;
7. e1.e = e3;
8. e2 = null;
9. e3 = null;
10. e2.e = e1;
11. e1 = null;
12. }
13. Eco e;
14. }
At what point is only a single object eligible for GC?


A. After line 8 runs.
B. After line 9 runs.
C. After line 10 runs.
D. After line 11 runs.
E. Compilation fails.
F. Never in this program.
G. An exception is thrown at runtime.
Answer:
g is correct.....

i am unable to underatand...can any one help me

[Ramu Valivarthi]

Hi
please go thru the following code.

class Eco {
Eco e;
public static void main(String[] args) {
Eco e1 = new Eco();
Eco e2 = new Eco();
Eco e3 = new Eco();
e3.e = e2;
System.out.println(""+e3.e);
e1.e = e3;
System.out.println(""+e1.e);
e2 = null;
System.out.println(""+e2);
e3 = null;
System.out.println(""+e3);
e2.e = e1;//here it will gives the NullPointerException
//Because you are nulling the reference variable e2 at line11.

System.out.println(""+e2.e);
e1 = null;
} }